The present invention relates in general to the detection of objects buried in soil and, more particularly, to the detection and identification of buried objects using acoustic energy.
The detection of buried objects is important for numerous modern day activities including, for example, utility servicing, law enforcement, military operations, and excavations. Accordingly, a wide variety of technologies and techniques have been pursued for detection of a diversity of buried objects including pipelines, electrical utilities, cadavers, landmines, underground cavities, and tunnels.
There has been qualified success for each technology and application with detection limitations generally being related to: the physical nature of the object, in terms of size, volume and composition; the type of soil and terrain; and, the depth of the object beneath the surface of the soil. Successful applications have included ground penetrating radar to detect plastic pipes in dry soils, infrared detection of cadavers in shallow graves, and acoustic-seismic detection of a multitude of different objects buried beneath various soil types ranging from unlithified marine sediments to railroad ballast. There has been very limited success in attempts to use techniques employing mechanical radiation to detect buried pipes, archeological remains, voids under pavement, various nonmetallic objects, landmines, and cadavers.
In view of the limited success of several of the previously employed techniques, it is apparent that "sensing" an object is not the major hurdle. Instead, since numerous buried objects may be detected or sensed by a given sensing technique, a more difficult problem is the recognition or identification of an object once it has been detected. Unfortunately, the known prior art sensing arrangements have been even less successful in the identification of buried objects than in the detection of the objects.
Accordingly, there is a need for an improved arrangement for detecting and identifying objects buried in soil.